CANCUN, Mexico--Mexico is pushing parties at the United Nations climate change meeting to strive for the best possible deal, although even the most ambitious agreement will fall short of what is needed to deal with climate change.

Acknowledging that thorny issues such as agreeing to a second round of greenhouse gas emissions cuts under the Kyoto Protocol are unlikely to be resolved at the talks at the beach resort of Cancun, Mexico's top climate change diplomat told reporters that he feels a major step forward could be made.

"The big challenge is not to just capture in a United Nations document the commitments and actions of developed and developing countries, but to find a way on one hand to increase these...and find a mechanism to keep going," said Luis Alfonso de Alba at a news conference.

Progress on a new global climate change agreement has been slow as developed countries complain that the United Nations' 1992 climate convention is outdated, focusing too much on them when China's rapid economic growth has made it the world's top carbon emitter.

Most countries agreed on a formula at last year's Copenhagen summit whereby industrialized countries would cut their emissions while emerging economies took "climate actions" to slow growth in greenhouse gases. Objections by some nations prevented it, however, from being formally adopted by the U.N.

"Kyoto covered at most 28 percent of global emissions and had goals that barely surpassed 5 percent of global emissions," de Alba said. "In Cancun we are hoping to come out with a package of emissions reductions that will certainly, if what countries have announced is made concrete, will surpass 18 or 19 percent on a global level."

Deal needed The cuts envisioned by parties at Cancun fall short of what scientists say is needed to limit the rise in average global temperatures to less than 2 degrees Celsius, de Alba said, but a deal would breath new life into the multilateral process.

The Cancun meeting has seen so far little of the rancor and inflexibility that marked the Copenhagen summit as negotiators appear to have accepted that an incremental approach is the best that can be hoped for at this time.

The most controversy has come from Japan's claim that extending the Kyoto protocol is "meaningless" without a broader pact that includes China and the United States, the world's top two emitters of greenhouse gases.

The stance of Japan, and some other countries including Canada and Russia over Kyoto, has prompted accusations by environmental groups and some developing countries that rich nations are trying to shirk their commitments.

"Everyone is for the continuity of Kyoto, but in some manner this is linked to complementary or additional efforts. What we have to be aware of is that we have a brief period to take decisions but this period ends in 2012, not the end of Cancun," de Alba said.

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